The most widely used microbial pesticides are derived from the bacterium Bacillus thuringiensis. This bacterial agent is used to control a wide range of leaf-eating caterpillars, beetles and mosquitos. Bacillus thuringiensis produces a proteinaceous paraspore or crystal which is toxic upon ingestion by a susceptible insect host. For example, B. thuringiensis var. kurstaki HD-1 produces a crystal called a delta endotoxin which is toxic to the larvae of a number of lepidopteran insects. The cloning and expression of this B.t. crystal protein gene in Escherichia coli has been described in the published literature (Schnepf, H. E. and Whitely, H. R. [1981] Proc. Natl. Acad. Sci. USA 78:2893-2897). U.S. Pat. No. 4,448,885 and U.S. Pat. No. 4,467,036 both disclose the expression of B.t. crystal protein in E. coli. U.S. Pat. No. 4,853,331 discloses B. thuringiensis strain san diego (B.t. sd.) which can be used to control coleopteran pests in various environments. U.S. Pat. No. 4,849,217 discloses Bacillus thuringiensis isolates active against the alfalfa weevil. One of the isolates disclosed is B. thuringiensis PS86A1 (NRRL B-18400).